Michael Barbaro called it a "sizable figure," noting it was collected over a relatively short period, between January 12 and March 11.

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"I certainly think if Joe Lhota 730,000, then he's in the game," said the Manhattan Republican County Chairman, Dan Isaacs, who is supporting Lhota's main rival, John Catsimatidis, a billionaire oil and supermarket magnet who is self-financing his campaign.

One Republican operative not associated with any campaign said Lhota would have probably raised more money if Catsimatidis wasn't running.

One key figure will be how much money Lhota has left over after paying start-up costs to launch his campaign, on top of fund-raising costs. One Republican operative not associated with any campaign said if Lhota has $500,000 left on hand after those costs, he's in great shape.

For Catsimatidis, who has already sent 400,000 robocalls and began airing radio ads, the key details to look at are his expenses. Specifically, how much he's given to local Republican clubs and organizations.

Catsimatidis' money has already helped him win the support of two Republican county chairman, Isaacs in Manhattan and Phil Ragusa in Queens. Craig Eaton, the chairman in Brooklyn, is signaling his openness to supporting Catsimatidis also.

Isaacs told me he hasn't received any new contribution from Catsimatidis, but in the future, he'd like to.

"I certainly hope they would be forthcoming," he said. "As you know, it's tough raising money [and] to be a Republican, so any assistance is much appreciated. But we'll see. Hopefully, there will be."

Another Republican operative not affiliated with any campaign said it's worth seeing if Catsimatidis paid for a poll. Money isn't an object for him, and he's already devoted money, at an unusually early point, to highly discretionary robocalling activity.

Lhota, by contrast, is just getting off the ground and has had to focus on raising money. Paying for a poll probably wasn't a priority.

Another candidates running in the Republican primary is George McDonald, the Doe Fund founder who is raising money under the state donation limits, which are much higher than the limits set by the New York City Campaign Finance Board. McDonald is in court fighting for the right to do this, arguing that he's not accepting matching funds from the city, therefore, shouldn't be limited by their limits.

Also running is local publisher Tom Allon, who left the Democratic Party after failing to gain traction among voters and donors.

Adolfo Carrion, the Independence Party nominee, is hoping to run in the Republican primary, but might not get in.